the only issue i see is most blackout rifles come with a 1-8 twist and that with short 30 caliber bullets don't mix. I spoke with a barrel manufacturer as I was considering a 300BLK in a Contender for my kids, and he flat out told me the 300BLK was and always will be originally designed to be fired subsonic and suppressed. Unless you can find a rifle with a 1-10 or 1-12 twist, those 110-150gr bullets won't do good in accuracy (according to this barrel maker).
He recommended in a Contender go with 6.8SPC, 7-30 Waters or 30-30 and use low recoil loads if need be.
In your case, I would say 223 with a 1-8 or 1-9 twist, and any good 60 to 69gr hunting style bullet. It's every bit as good as a 243 in my experience as the BC of the bullets are really good.
